/**
 * Created by zhengxingquan on 2017/9/5.
 */
(function ($) {
    function calcDisableClasses(oSettings) {
        var start = oSettings._iDisplayStart;
        var length = oSettings._iDisplayLength;
        var visibleRecords = oSettings.fnRecordsDisplay();
        var all = length === -1;

        // Gordey Doronin: Re-used this code from main jQuery.dataTables source code. To be consistent.
        var page = all ? 0 : Math.ceil(start / length);
        var pages = all ? 1 : Math.ceil(visibleRecords / length);

        var disableFirstPrevClass = (page > 0 ? '' : oSettings.oClasses.sPageButtonDisabled);
        var disableNextLastClass = (page < pages - 1 ? '' : oSettings.oClasses.sPageButtonDisabled);

        return {
            'first': disableFirstPrevClass,
            'previous': disableFirstPrevClass,
            'next': disableNextLastClass,
            'last': disableNextLastClass
        };
    }

    function calcCurrentPage(oSettings) {
        return Math.ceil(oSettings._iDisplayStart / oSettings._iDisplayLength) + 1;
    }

    function calcPages(oSettings) {
        return Math.ceil(oSettings.fnRecordsDisplay() / oSettings._iDisplayLength);
    }

    var firstClassName = 'first';
    var previousClassName = 'previous';
    var nextClassName = 'next';
    var lastClassName = 'last';

    var paginateClassName = 'paginate';
    var paginateOfClassName = 'paginate_of';
    var paginatePageClassName = 'paginate_page';
    var paginateInputClassName = 'paginate_input';

    $.fn.dataTableExt.oPagination.input = {
        'fnInit': function (oSettings, nPaging, fnCallbackDraw) {
            var nFirst = document.createElement('span');
            var nPrevious = document.createElement('span');
            var nNext = document.createElement('span');
            var nLast = document.createElement('span');
            var nInput = document.createElement('input');
            var nPage = document.createElement('span');
            var nOf = document.createElement('span');

            var language = oSettings.oLanguage.oPaginate;
            var classes = oSettings.oClasses;

            nFirst.innerHTML = language.sFirst;
            nPrevious.innerHTML = language.sPrevious;
            nNext.innerHTML = language.sNext;
            nLast.innerHTML = language.sLast;

            nFirst.className = firstClassName + ' ' + classes.sPageButton;
            nPrevious.className = previousClassName + ' ' + classes.sPageButton;
            nNext.className = nextClassName + ' ' + classes.sPageButton;
            nLast.className = lastClassName + ' ' + classes.sPageButton;

            nOf.className = paginateOfClassName;
            nPage.className = paginatePageClassName;
            nInput.className = paginateInputClassName;

            if (oSettings.sTableId !== '') {
                nPaging.setAttribute('id', oSettings.sTableId + '_' + paginateClassName);
                nFirst.setAttribute('id', oSettings.sTableId + '_' + firstClassName);
                nPrevious.setAttribute('id', oSettings.sTableId + '_' + previousClassName);
                nNext.setAttribute('id', oSettings.sTableId + '_' + nextClassName);
                nLast.setAttribute('id', oSettings.sTableId + '_' + lastClassName);
            }

            nInput.type = 'text';
            nPage.innerHTML = 'Page ';

            nPaging.appendChild(nFirst);
            nPaging.appendChild(nPrevious);
            nPaging.appendChild(nPage);
            nPaging.appendChild(nInput);
            nPaging.appendChild(nOf);
            nPaging.appendChild(nNext);
            nPaging.appendChild(nLast);

            $(nFirst).click(function() {
                var iCurrentPage = calcCurrentPage(oSettings);
                if (iCurrentPage !== 1) {
                    oSettings.oApi._fnPageChange(oSettings, 'first');
                    fnCallbackDraw(oSettings);
                }
            });

            $(nPrevious).click(function() {
                var iCurrentPage = calcCurrentPage(oSettings);
                if (iCurrentPage !== 1) {
                    oSettings.oApi._fnPageChange(oSettings, 'previous');
                    fnCallbackDraw(oSettings);
                }
            });

            $(nNext).click(function() {
                var iCurrentPage = calcCurrentPage(oSettings);
                if (iCurrentPage !== calcPages(oSettings)) {
                    oSettings.oApi._fnPageChange(oSettings, 'next');
                    fnCallbackDraw(oSettings);
                }
            });

            $(nLast).click(function() {
                var iCurrentPage = calcCurrentPage(oSettings);
                if (iCurrentPage !== calcPages(oSettings)) {
                    oSettings.oApi._fnPageChange(oSettings, 'last');
                    fnCallbackDraw(oSettings);
                }
            });

            $(nInput).keyup(function (e) {
                // 38 = up arrow, 39 = right arrow
                if (e.which === 38 || e.which === 39) {
                    this.value++;
                }
                // 37 = left arrow, 40 = down arrow
                else if ((e.which === 37 || e.which === 40) && this.value > 1) {
                    this.value--;
                }

                if (this.value === '' || this.value.match(/[^0-9]/)) {
                    /* Nothing entered or non-numeric character */
                    this.value = this.value.replace(/[^\d]/g, ''); // don't even allow anything but digits
                    return;
                }

                var iNewStart = oSettings._iDisplayLength * (this.value - 1);
                if (iNewStart < 0) {
                    iNewStart = 0;
                }
                if (iNewStart >= oSettings.fnRecordsDisplay()) {
                    iNewStart = (Math.ceil((oSettings.fnRecordsDisplay()) / oSettings._iDisplayLength) - 1) * oSettings._iDisplayLength;
                }

                oSettings._iDisplayStart = iNewStart;
                fnCallbackDraw(oSettings);
            });

            // Take the brutal approach to cancelling text selection.
            $('span', nPaging).bind('mousedown', function () { return false; });
            $('span', nPaging).bind('selectstart', function() { return false; });

            // If we can't page anyway, might as well not show it.
            var iPages = calcPages(oSettings);
            if (iPages <= 1) {
                $(nPaging).hide();
            }
        },

        'fnUpdate': function (oSettings) {
            if (!oSettings.aanFeatures.p) {
                return;
            }

            var iPages = calcPages(oSettings);
            var iCurrentPage = calcCurrentPage(oSettings);

            var an = oSettings.aanFeatures.p;
            if (iPages <= 1) // hide paging when we can't page
            {
                $(an).hide();
                return;
            }

            var disableClasses = calcDisableClasses(oSettings);

            $(an).show();

            // Enable/Disable `first` button.
            $(an).children('.' + firstClassName)
                .removeClass(oSettings.oClasses.sPageButtonDisabled)
                .addClass(disableClasses[firstClassName]);

            // Enable/Disable `prev` button.
            $(an).children('.' + previousClassName)
                .removeClass(oSettings.oClasses.sPageButtonDisabled)
                .addClass(disableClasses[previousClassName]);

            // Enable/Disable `next` button.
            $(an).children('.' + nextClassName)
                .removeClass(oSettings.oClasses.sPageButtonDisabled)
                .addClass(disableClasses[nextClassName]);

            // Enable/Disable `last` button.
            $(an).children('.' + lastClassName)
                .removeClass(oSettings.oClasses.sPageButtonDisabled)
                .addClass(disableClasses[lastClassName]);

            // Paginate of N pages text
            $(an).children('.' + paginateOfClassName).html(' of ' + iPages);

            // Current page numer input value
            $(an).children('.' + paginateInputClassName).val(iCurrentPage);
        }
    };
})(jQuery);
